/* ══════════════════════════════════════════════════════════════════════════
   build-guide.css — page styles for build-your-first-aquarium.php

   Scope: this file styles ONE page. Everything else comes from tokens.css and
   public.css. Rules of the house that apply here:
     · Text colour uses only --text / --text2 / --muted / --faint.
     · Section rhythm comes from the shared .section class; nothing below
       re-declares vertical section padding.
     · The eight build phases are SEQUENTIAL, so they are NOT .feature-card
       (see docs/design-audit.md → Accent Card System, usage rule E). They get
       their own numbered-timeline treatment, with accent used sparingly via the
       existing .a-* classes, which set --accent and nothing else.
     · Enhancement is CSS-only (hover/transition). No reveal-on-scroll, so
       nothing can end up stuck invisible.
     · Breakpoints: 900 / 640 / 400 only.
   ══════════════════════════════════════════════════════════════════════════ */

/* The intro block owns the top of the page; the first .full-divider follows it
   directly, so its trailing gutter is dropped in favour of --section-y below. */
.bg-top{padding-bottom:0}

/* ── Roadmap: the eight phases at a glance ──────────────────────────────── */
.bg-roadmap-head{max-width:var(--prose-width);margin:0 auto 28px}
.bg-roadmap-head p{color:var(--text2)}

.bg-steps{
  list-style:none;margin:0 auto;padding:0;
  max-width:var(--prose-width);
  position:relative;
}
/* the connecting rail — sits behind the numbered markers */
.bg-steps::before{
  content:"";position:absolute;left:19px;top:14px;bottom:14px;width:2px;
  background:linear-gradient(180deg,
    rgba(var(--accent-purple),.55),
    rgba(var(--accent-blue),.55) 45%,
    rgba(var(--accent-green),.55) 78%,
    rgba(var(--accent-amber),.55));
}
.bg-step{position:relative;padding:0 0 22px 58px}
.bg-step:last-child{padding-bottom:0}
.bg-step-num{
  position:absolute;left:0;top:0;
  width:40px;height:40px;border-radius:12px;
  display:flex;align-items:center;justify-content:center;
  font-size:0.9375rem;font-weight:700;font-variant-numeric:tabular-nums;
  color:rgb(var(--accent));
  background:linear-gradient(150deg,rgba(var(--accent),.22),rgba(var(--accent),.06));
  border:1px solid rgba(var(--accent),.35);
}
.bg-step-link{
  display:block;text-decoration:none;
  border:1px solid var(--border);border-radius:12px;
  background:var(--bg2);
  padding:12px 16px;
  transition:border-color .18s,background .18s,transform .18s;
}
.bg-step-link:hover{
  border-color:rgba(var(--accent),.5);
  background:var(--surface-2);
  transform:translateX(3px);
  text-decoration:none;
}
.bg-step-eyebrow{
  display:block;font-size:var(--fs-xs);font-weight:600;
  text-transform:uppercase;letter-spacing:.1em;
  color:rgb(var(--accent));margin-bottom:5px;
}
.bg-step-title{display:block;font-size:1rem;font-weight:600;color:var(--text);margin-bottom:4px}
.bg-step-desc{display:block;font-size:0.9rem;line-height:1.55;color:var(--text2)}

/* ── Phase headers inside the long-form body ───────────────────────────── */
.bg-phase{
  display:flex;align-items:center;gap:12px;
  margin:44px 0 14px;
}
.bg-phase-num{
  flex:0 0 auto;
  width:34px;height:34px;border-radius:10px;
  display:flex;align-items:center;justify-content:center;
  font-size:0.875rem;font-weight:700;font-variant-numeric:tabular-nums;
  color:rgb(var(--accent));
  background:rgba(var(--accent),.12);
  border:1px solid rgba(var(--accent),.32);
}
.bg-phase-label{
  font-size:var(--fs-xs);font-weight:600;text-transform:uppercase;
  letter-spacing:.1em;color:var(--muted);
}
/* the h2 that follows a phase header sits tight under it */
.prose .bg-phase + h2{margin-top:0}

/* ── Decision / reasoning / common mistake ─────────────────────────────── */
.bg-dl{
  margin:20px 0 8px;
  border:1px solid var(--border);border-radius:12px;
  background:var(--bg2);
  overflow:hidden;
}
.bg-dl-row{padding:14px 18px;border-top:1px solid var(--border)}
.bg-dl-row:first-child{border-top:none}
.bg-dl-k{
  font-size:var(--fs-xs);font-weight:600;text-transform:uppercase;
  letter-spacing:.09em;color:var(--muted);margin-bottom:6px;
}
.bg-dl-v{font-size:0.95rem;line-height:1.6;color:var(--text2)}
.bg-dl-v strong{color:var(--text);font-weight:600}
.bg-dl-mistake .bg-dl-k{color:var(--faint)}

/* ── Evidence signposting ──────────────────────────────────────────────── */
.bg-evidence{
  margin:20px 0;padding:14px 18px;
  border:1px solid var(--border);border-left:3px solid rgba(var(--accent),.7);
  border-radius:0 10px 10px 0;background:var(--bg2);
}
.bg-evidence-k{
  font-size:var(--fs-xs);font-weight:600;text-transform:uppercase;
  letter-spacing:.09em;color:rgb(var(--accent));margin-bottom:6px;
}
.prose .bg-evidence p{font-size:0.95rem;color:var(--text2);margin-bottom:0}
.prose .bg-evidence p + p{margin-top:10px}

/* ── The parallel tools grid (legitimately .feature-card) ──────────────── */
/* Section layer sets grid sizing only — card visuals stay in public.css. */
.bg-tool-head{max-width:var(--prose-width);margin:0 auto 28px}
.bg-tool-head p{color:var(--text2)}
.bg-tool-grid{display:grid;grid-template-columns:repeat(4,1fr);gap:16px}
.bg-tool-grid .feature-card{padding:24px 22px 22px}
.bg-tool-grid .fc-icon{width:46px;height:46px;border-radius:12px;margin-bottom:16px}

/* ── Closing block ─────────────────────────────────────────────────────── */
.bg-close{max-width:var(--prose-width);margin:0 auto}
.bg-actions{display:flex;flex-wrap:wrap;gap:12px;margin-top:26px}

/* ── Responsive ────────────────────────────────────────────────────────── */
@media(max-width:900px){
  .bg-tool-grid{grid-template-columns:repeat(2,1fr)}
}
@media(max-width:640px){
  .bg-tool-grid{grid-template-columns:1fr}
  .bg-step{padding-left:52px}
  .bg-steps::before{left:17px}
  .bg-step-num{width:36px;height:36px;border-radius:10px}
  .bg-phase{margin-top:36px}
  .bg-actions{flex-direction:column;align-items:stretch}
  .bg-actions .btn-primary,.bg-actions .btn-secondary{justify-content:center;width:100%}
}
@media(max-width:400px){
  .bg-step{padding-left:46px}
  .bg-steps::before{left:15px}
  .bg-step-num{width:32px;height:32px;font-size:0.875rem}
  .bg-step-link{padding:11px 13px}
  .bg-dl-row{padding:13px 14px}
}

/* ── Motion ────────────────────────────────────────────────────────────── */
@media(prefers-reduced-motion:reduce){
  .bg-step-link{transition:none}
  .bg-step-link:hover{transform:none}
}